1. Field of the Invention
This invention relates to systems for and methods of generating and manipulating edit decision lists which corresponds to edit events of a video which has been digitally edited; and particularly relates to systems and methods for managing edit decision lists having dissimilar formats.
2. Description of Related Art
The edit decision list (EDL) was developed by the CMX Corporation around 1974 for use with the CMX on-line video editor, the CMX 340, which digitally edits a video or a video version of film. The EDL is created as a record of the digital video editing and is thereby a means of capturing, defining, and recording the editing decisions made during a video editing session for use at a later time to, physically conform a film to the edit decisions, or to create a duplicate of the edited video. The EDL is a formatted list of the editing "events" defined during an editing session. Each "event" is a single editing action, such as a cut, dissolve, or wipe. The EDL contains all data necessary to uniquely describe each event.
Use of EDLs as a video editing record has been widely accepted by manufacturers of digital video editors. While a few video editors produce EDLs in a format which is closely compatible with the CMX EDL format, many video editors use a modified EDL format to represent features unique to their editing systems. This has led to a proliferation of diverse EDL formats.
The diversity of EDL formats has led to problems in recreating editing decisions on systems other than that on which an EDL was originally created. Incompatibility of formats is problem when, for example, a variety of off-line editors are used to generate EDLs for a single on-line editor. Even video editing systems which claim to produce CMX-compatible EDLs include format variations relating to the amount and accuracy of information represented in those systems.
Several commercial EDL management and conversion utilities exist, for example, these three utilities: Shot Lister, SEDL, and EDL TRANSform, which is sold by Amtel, Inc. Typically, These utilities accommodate only a fixed set of EDL formats, which are directly supported in software, with no mechanism for extending of changing to additional formats. TRANSform is an exception in that this system allows EDL formats to be defined by a C scanf specification, to thereby accommodate a range of existing EDL formats. However, this system has many deficiencies. For example, TRANSform can not process editing events which require several lines of code to describe them, and does not allow for optional elements of events, concatenated event description fields, events other than cuts, or well-known spacing. Furthermore, the system is based on a cumbersome protocol which is quite difficult for a user to understand. The present invention addresses all of these deficiencies.